Sorry for reviving an old topic, but these days I’m catching up on my Sageuks and came across this topic while searching through the discussions. Instead of making a new list, I wanted to reply to this one.
Seen:
Queen Seon Duk (2009) - First Sageuk I watched and the reason why I still watch K-dramas till this day
Arang and the Magistrate (2012)
Bridal Mask (2012)
Faith (2012)
Jewel in the Palace(2003)
Dong Yi(2010)
Iljimae
Moon Embracing the Sun (2012)
Sungkyunkwan Scandal
Moonlight Drawn By Clouds
Gu Family Book
Hwarang: The Poet Warrior Youth
Dr. Jin
Tree with deep roots
Six flying dragons
The flower in prison - watching this right now
Rooftop prince
Chuno AKA Slave Hunters
Mr Sunshine (is this a Sageuk?)
Grand Prince
Updated:
Empress Ki
Haven’t seen from your lists (oh so many!)
JeJoongwon (2010)
Yi San(2007)
Moon Lovers: Scarlet Heart Ryeo (2016)
Painter of the Wind’
Horse doctor
Hong Gil Dong
Damo
Hur Jun
Jang Yeong-sil
Soldier aka God of War 
The crying woman
The legend
Legend of Hyang Dan
Warrior Baek Dong-soo
The Princess’ Man (2011)
Scholar Who Walks the Night
Queen In Hyun’s Man
Secret door
Mirror of the witch
Jackpot
Jumong
Ballad of Seo Dong (YES!)
Gye Baek
Shine or Go Crazy
Empress Chunchu / the Iron Empress
Queen Insoo
Saimdang, Light’s Diary
The King’s Face
The Return of Iljimae
Cruel Palace - War of Flowers
Tamra, the Island
Jang Ok Jung Live in Love
Rebel thief who stole the people
The Kingdom of the Winds
Kim Soo Ro
Ja Myung Go
King Geunchogo
King Gwanggaeto
King’s Daughter Su Baek Hyang
The Blade and Petal
The Great King’s Dream
The Emperor of the Sea
Emperor Wang Gun
Age of Warriors
Shin Don
The Great Seer
Jeong Do-jeon
Daewang Sejong
The Divine Weapon
Heo Nanseolheon
The King and I
The Night Watchman
The Three Musketeers -
Secret Investigation Record
Hwang Jin Yi
Heaven’s Will / Gunmen of Joseon
NIm Kyeok Jeong
Queen of seven days
Ya Cha AKA Yaksha
Ruler of the mask
The Immortal Lee Soon-Shin
Jing Birok / the book of corrections
Jung Yi, The Goddess of Fire
Splendid Politics Aka Hwajung
Joseon X-files - (1609)
Masquerade - (1619)
Strongest Chil Woo -
The Great Merchant Kim Man Deok
Jung Yak Yong -
Seoul’s Sad Song/Conspiracy in the Court / Eight Days Mystery of Jeongjo Assassination
Sangdo
The Merchant: Gaekju 2015
Chosun Police
Maids
The Sword With No Name
Jeon Woo Chi
Bichunmoo
Tears of the Dragon
Yeon gae samun
Between this and Chinese historical dramas, I don’t know where I’d find the time to watch them all haha.